Method of bonding elastomers to other materials and adhesive compositions used therefor



United States Patent METHOD OF BONDING ELASTOMERS TO OTHER MATERIALS ANDADHESIVE COMPOSITIONS USED THEREFOR Homer W. Paxton, Passaic, N. J.,assignor to United States Rubber Company, New York, N. Y., a corporationof New Jersey No Drawing. Application August 31, 1954 Serial No. 453,415

13 Claims. (31. 154-139) This invention relates to new adhesives forbonding elastomers to themselves or to other materials. In a preferredform, it relates to adhesives for bonding elastomers to textilematerials such as nylon, rayon, or cotton.

This application is a continuation-in-part of my application Serial No.385,265, filed October 9, 1953, now abandoned.

Heretofore, it has been extremely difiicult to'bond elastomers to nylon,and only slightly less difiicult to bond them to rayon. Usually, atleast two or three coats of an adhesive whose composition must be variedfrom one coat to the next must be used. This complex operation obviouslygreatly increases the cost of bonding the elastomer to the textilematerial, as in making tires, footwear, or other compositeelastomer-fabric articles. The bonding of elastomers to cotton is notusually as difiicult as the bonding of elastomers to nylon, rayon, orother synthetic fibers, but even with cotton it is sometimes necessaryto resort to complicated and expensive operations such as the use ofmultiple coatings.

It has now been found that these difficulties can be eliminated by theuse of a new class of bonding agents. These new agents are made from amixture of a certain phenolic resin with an adduct, made at hightemperature, i. e., about 175225 C., of an olefinic elastomer and maleicanhydride. The components are dissolved or dispersed in an organicliquid to form the new adhesive cements of this invention.

The elastomer-maleic anhydride adducts usually are made by chemicalreaction between the two said materials in the presence of one or moreinhibitors of free-radical polymerization.

The elastomer can be any which has olefinic unsaturation, e. g., Hevearubber and any synthetic rubber which has at least 1% olefinicunsaturation; i. e., is a polymer made from at least 1% of a conjugateddiolefin. These synthetic rubbers can be either homopolymers orheteropolymers of such a diolefin. Typical of such elastomers arepolybutadiene, polyisoprene, the styrenezdiolefin copolymers (knowngenerically as GR-S), the acrylonitrile: diolefin copolymers (knowngenerically as GR-A), the

acrylic esterzdiolefin copolymers, the monovinylpyridine:

diolefin copolymers, and the isobutylenezdiolefin copolymers (knowngenerically as Butyl rubbers and as GR-I).

The adducts are not fully equivalent among themselves, either in themethod of preparation or in their use in the adhesives of thisinvention.

The elastomers used in making the. adducts are divisible into thefollowing groups according to their behavior during preparation of themaleic adducts: namely,

the natural rubbers, e. g., Hevea rubber; the highly unsaturatedsynthetic rubbers, e. g., GR-S, GR-A, the

acrylatezdiolefin elastomers, the vinylpyridinezdiolefin elastomers andpolybutadiene; and the Butyl rubbers.

Hevea rubber reacts chemically with maleic anhydride at a temperaturebetween 175 C. and 225 C. to form ice adducts which can be processed onconventional rubber machinery and can be dissolved in suitable organicsolvents. This reaction is preferably carried out in an internal rubbermixer such as a Banbury. Customarily, one or more inhibitors offree-radical polymerization are added to the mixture before the reactiontakes place. While adducts suitable for use in this invention can bemade in the absence of such inhibitors, the adducts made in theirpresence have lower gel content and are more easily made into cementsthan are the adducts made in the absence of said inhibitors.

In contrast, .the adducts of the highly unsaturated synthetic elastomersmust be made in the presence of inhibitors of free-radicalpolymerization. In the absence of such inhibitors, unprocessable,insoluble, crumbly materials are obtained. The adducts of thesesynthetic elastomers are preferably made in a Banbury. These new adductsare described in a copending application by Snyder and Paxton, SerialNo. 342,748, filed March 16, 1953, now abandoned. I

The adducts of Butyl rubber are made in the absence of inhibitors otherthan those incorporated in the rubber during its manufacture. In fact,even such inhibitors are unnecessary for the successful operation ofthis invention.

Typical adducts are made as follows, all parts being by weight:

PROCESS A (For highly unsaturated synthetic elastomers) One, or amixture of two or more, high-unsaturation, synthetic elastomers parts)is masticated in a Banbury mixer for a short time at -150 C. Then onepart of N-phenyl-beta-naphthylamine, one part of triphenyl phosphite andthe desired amount of maleic anhydride are added in the order listed, asrapidly as possible, and mixed for. a short time. The mixing operationcauses the temperature to rise, and the heating may be aided by"external heat. The addition reaction begins when the temperature ofthemixture has risen to about C. The temperature of the mixture is held at205-235 C. until the reaction appears to be complete. (This time ofreaction varies, depending on the size of the mixer and batch, thetemperature, and on the proportion of maleic anhydride added, roughlybetween 10 and 60 minutes.) Heat is turned OE and cooling water turnedon. Then one part each of BLE (an acetonediphenylamine condensate) andof 2,6-ditert.-butyl-4- methylphenol are added and mixed in. Finally,the product is removed from the Banbury and shected out on a cold millfor storage or immediate use. These amounts of inhibitors mentioned arein addition to that amount customarily incorporated in the elastomerduring manufacture.

The adducts of maleic anhydride and synthetic elasto mers can be made bymany variations of this process, as described by Snyder et al., loc.cit. I can use in my process adducts made by any of the methods and inthe presence of any of the inhibitors disclosed by Snyder et al.

PROCESS B (For Hevea rubber) The adducts of Hevea rubber and maleicanhydride are made by process A except that the inhibitors can beomitted, if desired. However, my preferred adhesives are made from Heveaadducts made in the presence of the inhibitors. 1

.The amount of maleic anhydride used in making these new adducts byprocesses A and B can be varied widely, as described in the said Snyderet al. application. When the adducts are to be used in the new adhesivesof this invention a feed ratio between about 3 parts and 1. parts ofmaleic anhydride per 100 parts of elastomer is suitable. Preferably, thefeed ratio is between about parts and 12 parts of maleic anhydride per100 parts of elastomer. The amountof maleic anhydride which combineswith the elastomer is always somewhat less than that in the feed becausesome of it vaporizes and escapes from the Banbury. The amount of loss,of course, varies with the individual Banbury, the time, the operatingtemperature, and with the amount of maleic anhydride in the feed, sothat the exact amount of combined maleic anhydride varies. However, by afew simple experiments the feed ratio to be used under any givenconditions can be determined, and the operation standardized for thatparticular Banbury. The reaction is continued until substantially all ofthe unvolatilized maleic anhydride has reacted, the completion of thereaction being shown by the substantial absence of the odor of maleicanhydride in the hot adduct.

PROCESS C (For Butyl rubber) A charge of 100 parts of Butyl rubber and5-10 parts of maleic anhydride is mixed in a Banbury for a few minutesat a low temperature, e. g., below 100 C., to efiect uniform dispersion.Then 1,3 dichloro 5,5 dimethylhydantoin (4 parts), an accelerator forthe desired reaction, is added, and the temperature of the mixture israised as rapidly as possible to 160-175 C., and held there for 30minutes by suitably adjusting the Banbury speed. During this time theadduct is formed. The stock then is dropped from the Banbury and storedat room temperature until used.

The use of the said accelerator and of other N-halogenated organiccompounds as accelerators for making Butyl adducts is disclosed by P. F.Gunberg in copending application, Serial No. 434,073, filed June 2,1954. Any of the modifications, e. g., change of accelerator, presenceof carbon black, etc., described by Gunberg can be used in makingadducts suitable for use in the adhesives of my invention. Otheraccelerators also can be used in making suitable adducts.

PROCESS D (For Butyl rubber) Alternatively, Butyl adducts can be madewithout an accelerator. The rubber and the maleic anhydride are mixed ona cold mill or in a cold Banbury in the proportion shown above. Themixture is then heated in an autoclave with 60 parts of benzene for sixhours at 180-200 C. to form the adduct. The benzene and excess maleicanhydride are separated from the adduct by extraction with methanol andthen with water. This operation is carried out at or near roomtemperature in order to prevent esterification or hydrolysis of theanhydride groups.

I prefer to use the accelerated process C in making butyl adductsbecause of its case. However, adducts made by process D areinterchangeable with those made by process C in the operation of thisinvention.

The synthetic elastomers usable in process A are the synthetichomopolymers of a conjugated diolefin and the high unsaturationheteropolymers thereof, containing at least 15% of such diolefin, withone or more monoolefinic compounds copolymerizable therewith, such asstyrene; a methylstyrene; an acrylic or methacrylic nitrile,

amide, acid or ester; a monovinylpyridine; a fumaric ester; vinylidenechloride; methyl vinyl ketone; and methylisopropenyl ketone.

The conjugated diolefin used in making the elastomers preferablycontains four to six carbon atoms. Commonly I use butadiene, but I canalso use isoprene, piperylene, or 2,3-dimethylbutadiene.

The proportion of the said diolefin in rubbery heteropolyrners thereofused in process A can be as little as about 15% of the total amount ofcopolymerizable mono- 4 mers, the remainder being mono-olefiniccompound. This proportion is customarily given as the feed ratio of thediolefin and the other monomer or monomers. Polymerization is generallybut not necessarily effected in aqueous emulsion, by well-knowntechniques.

The diolefin-styrene copolymers with which I start are genericallytermed GRS. They can be made by any of the commonly known methods ofcopolymerization, e. g., in emulsion at 50 C., 5 C., or 15 C.

The methylstyrene used can be alpha-methylstyrene, ortho-, meta-, orpara-methylstyrene, or a mixture of any of them.

The acrylic type nitrile, amide, acid or ester is one having thestructure CH2=C-Y wherein X is hydrogen or methyl, and Y is CN,

H O-N or -COOR, where R and R are hydrogen, alkyl or aralkyl groups. Themost widely used monomer from this group is acrylonitrile. Copolymers ofacrylonitrile and butadiene, generically known as GR-A, are soldcommercially under the names Paracril, Hycar, etc. Other importantmonomers in this group are the acrylic and methacrylic esters, such asmethyl acrylate, ethyl acrylate, methyl methacrylate, butyl acrylate and2-ethylhexyl acrylate.

The vinylpyridine can be an unsubstituted monovinylpyridine, e. g., 2-,3-, or 4-vinylpyridine, or it can be an alkyl-substitutedmonovinylpyridine, e. g., 2-methyl-5- vinylpyridine,5-ethyl-2-vinylpyridine, 2-methyl-6-vinylpyridine, and2-ethyl-4-vinylpyridine.

The fumaric esters have the structure wherein R" and R' are residuesfrom alcohols which can be alike or different.

The conjugated diolefin used in making the isobutylenezdiolefinelastomers used in process C and process D commonly is isoprene, butother diolefins, such as butadiene, piperylene or 2,3-dimethylbutadiene,can also be used.

The proportion of the diolefin in these elastomers can be varied betweenabout 1% and about 25%. The commercially available elastomers containabout 1-5% of conjugated diolefin combined.

The phenolic resin used in this invention is Durez 12687, which is aphenol-formaldehyde resin modified with cashew nut shell oil asdescribed by Shepard and Boiney U. S. Patent No. 2,532,374, resinexamples 4 and 6, and which contains sufficient hexamethylenetetramine(or equivalent source of formaldehyde) to complete the conversion of theresin to the insoluble, infusible state when heat is applied. A mixtureof Durez 12686 parts) and hexamethylenetetramine (at least 8 parts) isequivalent to Durez 12687.

As is well-known (see U. S. Patent No. 2,532,374), cashew nut shell oilcan serve as a source of material for condensation or reaction with aresinous phenol-aldehyde condensate to form, inthe presence of amethyleneyielding hardening agent (hexamethylenetetramine or its knownequivalent)an insoluble, infusible resinous product. See also U. S.Patent No. 2,532,374 for reference to the same type of infusibleproduct. Before hardening, the cashew nut shell oil-modifiedphenol-aldehyde condensate is a normally permanently fusible resin. It

' is such a modified resin which forms one of the essential componentsof the present organic solvent cement or adhesive composition. Theprimary phenols used are monohydric or polyhydric; e. g., phenol or itshomologs (including cresylic acid), resorcinol, etc. Phenol ispreferred, since together with formaldehyde, with which it is condensed,it furnishes the phenol-aldehyde portion of the cashew nut shelloil-modified commercial products known as Durez 12686 and 12687. Thelatter represent preferred embodiments used as the resinous portion ofthe present adhesive composition. The other essential component is themaleic anhydride-modified elastomer. Together the resin and the modifiedelastomer form a homogeneous mixture which when hardened by heat (withremoval of the inert solvent) forms a firm adhesive-bond for unitingtogether a wide variety of the same or different materials.

However, any cashew nut shell oil-modified phenolic resin made fromcashew nut shell oil and a simple phenol and capable of being advancedto the insoluble infusible form when subjected to the action of heatwhile in intimate admixture with a methylene-yielding substance,typified by hexamethylenetetramine, may be employed in the practice ofmy invention. For brevity, the resinous component of the present cementwill be referred toas a cashew nut shell oil-modified phenol-aldehyderesin, or more particularly as a cashew nut shell oil-modifiedphenol-formaldehyde resin.

The proportion by weight of adduct and resin can be varied between about50:50 and 90:10, preferably between about 60:40 and 85:15.

The adduct and the resin are dissolved in a suitable solvent or mixtureof solvents, either after being mixed on a rubber mill or by being addedseparately to the solvent.

When the adduct and the resin are pre-mixed in solid condition thesolvent is chosen for its ability to dissolve the adduct, regardless ofthe solubility of the resin in it. In general, the adducts are solublein the same solvents as the elastomers from which the adducts were made.For example, a mixture of a phenolic resin with an adduct made fromHevea rubber, GRS, a monovinylpyridine rubber, an acrylate rubber orGR-I can be dissolved in an aromatic hydrocarbon such as benzene,toluene, or a xylene even though the phenolic resin be substantiallyinsoluble in such a liquid. The adduct apparently either increases thesolubility of the resin in the hydrocarbon, or it keeps the resin in sofinely dispersed a state that it does not readily separate from thesolution. Regardless of the mechanism, I describe my invention hereinusing the terms solution and solvent. The adducts of acrylonitrileelastomers have limited solubility in aromatic hydrocarbons, but aresoluble in more polar liquids such as butanone. The phenolic resin alsois soluble in butanone.

When the adduct and the resin are dissolved separately, a suitablesolvent, not necessarily the same, must be chosen for each material. Theadduct is dissolved in an aromatic solvent, if soluble therein, or inbutanone; and the resin is dissolved in butanone. Subsequently, the twosolutions are mixed in any desired proportions.

The proportion of total solids in the solution is varied widelydepending on the method used to apply it to the materials to be bonded.Any conventional method of applying the cement can be used. If it is tobe sprayed, it is diluted to form a thin solution. If it is to beapplied by a dipping operation or with a brush, it is used in somewhatmore concentrated form. If it is to be applied with a doctor knife, itis used in such high concentration as to be almost a paste. However, theconcentration is not critical, and may be varied to suit the operation,as is obvious to anyone skilled in the art.

As stated above, the various adducts used in this invention are notfully equivalent among themselves. Depending on the materials which arebeing bonded together,

6 materials to be bonded is an elastomer. I have found that while all ofthe adhesives of this invention have good bonding ability, I normallyobtain the greatest bond strength when the adduct in the adhesive ismade from the same elastomer which is being bonded. For instance, Iprefer to bond Hevea rubber with an adhesive containing an adduct madefrom Hevea, to bond GR-S with an adhesive containing an adduct of GR-S,to bond Butyl rubber with an adhesive containing an adduct of Butylrubber, etc. However, I can also use adhesives containing adducts ofelastomers other than those being bonded.

My adhesives also are useful for bonding -still other elastomers such asneoprene (polychloroprene) and poly-. isobutylene.

My adhesives can be made from mixtures of two or more adducts of thesame elastomer differing in maleic anhydride content, or from mixturesof adducts made from different elastomers. My adhesives furthermore canbe made from adducts formed by reacting maleic anhydride with a mixtureof two or more elastomers;

such adhesives are particularly useful in bonding two differentelastomers together. Here again, in general, the elastomers used in themixed adducts are preferably the same as those being bonded.

My adhesives are valuable not only for bonding elastomers to each other,but also for bonding an elastomer to other materials such as textiles,metals, wood, paper, and plastic materials, or for bonding any of thesematerials to themselves or to each other. These new adhesives areparticularly useful in bonding elastomers to textile materials to formcomposite articles such as tires, rubbersoled shoes with cloth uppers,fire hose, garden hose, belting and diaphragms which have a fabricreinforcement. Typical textile materials are cotton, viscose rayon, andnylon, either uncoated or coated with long-chain quaternary ammoniumcompounds such as those used as waterproofing agents.

The following examples illustrate my invention. parts and percentagesare by weight.

EXAMPLE 1 All An adduct of Hevea rubber and maleic anhydride (feed ratio:10) made by process A was dissolved in toluene to form a 13% solution.Separately, Durez 12687 was dissolved in butanone to form a 25%solution. These two solutions were blended in the proportion of 100parts of the adduct solution and 22.3 parts of the resin solution,thereby forming a cement whose solid content was 70% adduct and 30%resin. This cement was brushed onto a nylon fabric and allowed to dry atroom temperature until the coating was tacky. A conventional,compounded, unvulcanized Hevea rubber stock was pressed against thecemented surface, and the composite article was then heated in a moldunder pressure for 45 minutes at C. (optimum conditions forvulcanization of the rubber stock) to form a rubber sheet inch thickhaving fabric adherent to the top surface. The composite sheet wascooled to room temperature, and cut into strips one inch wide. Thestrength of the adhesive was then measured, at room temperature and at100 C., and also at room temperature after being soaked in water for 24hours and then dried, by a standard stripping test on a Scott tensiletester. (All strengths are given in pounds per linear inch of width.)

The pulls required to cause failure were 55, 35 and 65 pounds,respectively, under the three test conditions. In all cases the rubberfailed rather than the adhesive.

To compare the strength of my new adhesive with one of the best of theadhesives conventionally used in the rubber industry, the commercialadhesive MDI-SO was applied to the nylon fabric according to themanufacturer's directions (du Pont Bulletin BL-230, dated February 25,1949), and then the same compounded Hevea stock was bonded to it by theprocess described above. The pull the adhesive is varied. In general, atleast one of the {5g rerruired to separate the rubber and fabricwas'only 20 7 pounds at room temperature (the other two tests were notmade). Failure occurred at the bond between rubber and fabric.

This example shows the tremendous superiority of my new cement over aconventional one widely used in the rubber industry.

EXAMPLE 2 Nylon fabric was bonded to a conventional Hevea shoe stock bythe new cement described in Example 1, and the laminate was heated ingaseous ammonia. for 60 minutes at 145 C. to vulcanize the shoe stock.The adhesion, determined at room temperature, as described in Example 1,was 26 pounds.

For contrast, various cements which do not illustrate this inventionwere also applied and tested in the same way. A cement of Hevea rubberdissolved in toluene gave only 0.5 pound pull; a cement of Durez 12687dissolved in butanone gave 5.8 pounds pull; and a cement made from themaleic anhydride adduct, described in Example 1, dissolved in toluene,gave 4 pounds pull.

Thus, it is evident that my new adhesive composed of the maleic adductand the phenolic resin is a very much stronger bonding agent than iseither of the solid ingredients used separately.

EXAMPLE 3 An adduct of GR-S 101 (a commercial cold GRS; feed ratio, 74butadiene226 styrene) and maleic anhydride (feed 7.5 parts per 100 partsof GRS) made by process A was dissolved in toluene to form a 19%solution. To it was added a 50% solution of Durez 12687 in butanone, inthe proportion of 100 parts of the adduct solution and 16.6 parts of theresin solution, to form a cement containing 23.6% total solids in theproportion 70% adduct and 30% resin. This cement was brushed onto anylon fabric and a viscose rayon fabric. These fabrics were thentreated, as shown in Example 1, except that they were plied to a GR-S101 stock which had been compounded conventionally. Vulcanization andtesting were carried out as described in Example 1. This cement gave 40pounds pull at room temperature with nylon, and 28 pounds pull withrayon.

This example shows that a typical GR-S can be used to make the adductportion of my new cements, and that both rayon and nylon can be bondedto elastomers.

Examples 1 and 3 show also that the proportion of elastomer to maleicanhydride can be varied.

EXAMI'LE 4 A 20% solution in toluene of the Heveatmaleic anhydrideadduct described in Example 1 was mixed with a 50% solution of Durez12687 in butanone in such proportion that the total solids of the cementconsisted of 71% of the adduct and 29% of the resin (100 parts of theadduct solution and 17 parts of the resin solution). This cement wasspread onto nylon fabric and bonded, as shown in Example 1, in one testto an unvulcanized Butyl rubber stock conventionally compounded withsulfur, and. in a second test to an unvulcanized Butyl rubber stockcompounded with a resin curative (as shown below). Both test pieces werevulcanized in a mold under pressure at 168 C. The piece vulcanized withsulfur was heated for 15 minutes, and the other one for 25 minutes. Ineach case the time was chosen to give the optimum cure of the Butylrubber. The time was not critical so far as the cement was concerned.The adhesion at room temperature, measured as shown in Example 1,between the nylon and the sulfur cured stock was 12 pounds; that betweenthe nylon and the resin-cured stock was 28 pounds.

The resin-cured Butyl rubber was compounded and cured by the processdisclosed by P. O. Tawney and J. R.

Little in a copending application, Serial No. 266,146, filed January 12,1952. This stock comprised:

Gar-15 1 i Carbon black 65 Amberol ST137 2 12 p-Toluenesulfonic acid 3 1EXAMPLE 5 A mastei'batch was made by blending 100 parts of theTiered-maleic anhydride adduct described in Example 1, 100 parts ofGR-l-lS, 65 parts of carbon black, 10 parts of Amberol ST137, 30 partsof Durez 12686, and 4 parts of para formaldehyde on a mill. Thismasterbatch was dispersed in toluene to form a cement having 25% totalsolids. This cement was used to bond nylon fabric to each of the Butylstocks shown in Example 4, and the plied stocks were cured as showntherein. The adhesion at room temperature was 15 pounds withsulfur-cured butyl, and 19 pounds with resin-cured butyl.

This example shows that the adduct and resin cements of this inventioncan be compounded with other materials.

EXAMPLE 6 Paracril C (acrylonitrilezbutadiene copolymer, 35:65) wasreacted with maleic anhydride in the proportion 100210 by process A.This adduct was blended on a mill with Durez 12687 in the proportion70:30. The blend was then dissolved in butanone. This cement was used tobond nylon fabric to Paracril C. Adhesion was very good.

EXAMPLE 8 A cement, made like that described in Example 7, except thatthe proportion of adduct:resin was 50:50, also gave good adhesionbetween nylon and Paracril C.

EXAMPLE 9 A mixture was made by blending 100 parts of a GR-115:maleicanhydride adduct (made by process D), 65 parts of carbon black, 30 partsof Durez 12687 and 10 parts of Amberol ST137 on a mill. This mixture wasdispersed in toluene to form a cement having 25% total solids.

This cement was used to coat nylon tire cord, which was then bonded inan H test mold to an unvulcanized Butyl stock which had beenconventionally compounded with sulfur, carbon black and accelerators.The test piece was vulcanized and then tested. (The H test is describedby Lyons, Nelson and Conrad, India Rubber World, 114, 213 et seq.(1946).) The pull required to separate the coated cord from the curedButyl stock was 16.5 pounds at room temperature. The adhesion betweenthe same Butyl stock and uucoated nylon cord; i. e., there was noadhesive layer, was only 4.8 pounds.

The new cement of Example 9 also was tested as a bonding agent betweenthe same cured Butyl stock and nylon fabric by the one-inch strippingtest described in Example 1. The adhesion was 43 pounds at roomtemperature, 10 pounds at 100 C., and 7 pounds at 121 C.

This example shows that adducts of Butyl rubber and maleic anhydride canbe used to form valuable cements according to my invention.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. An adhesive composition comprising a soluble, processable, chemicaladduct of maleic anhydride and an elastomer selected from the classconsisting of Hevea rubber; synthetic, rubbery homopolymers of anconjugated diolefin; rubbery heteropolymers of at most 85% of amonoolefinic compound and at least 15% of a conjugated diolefin; andrubbery copolymers of from about 95% to about 99% of isobutylene andfrom about to about 1% of a conjugated diolefin; and in addition acashew nut shell oil-modified phenol-aldehyde resin.

2. An adhesive composition comprising an organic solvent cement of asoluble, processable, chemical adduct of maleic anhydride and anelastomer selected from the class consisting of Hevea rubber; synthetic,rubbery homopolymers of a conjugated diolefin; rubbery heteropolymers ofat most 85% of a monoolefinic compound and at least 15% of a conjugateddiolefin; and rubbery copolymers of from about 95% to about 99% ofisobutylene and from about 5% to about 1% of a conjugated diolefin; andin addition a cashew nut shell oilmodified phenol-formaldehyde resin.

3. An adhesive composition comprising a chemical adduct of maleicanhydride and an elastomer selected from the class consisting of Hevearubber; synthetic, rubbery homopolymers of a conjugated diolefin;rubbery heteropolymers of at most 85 of a monoolefinic compound and atleast 15 of a conjugated diolefin, which adducts of the saidhomopolymers and heteropolymers are prepared in the presence of aninhibitor of freeradical polymerization; and rubbery copolymers of fromabout 95 to about 99% of isobutylene and from about 5% to about 1% of aconjugated diolefin; and in addition a cashew nut shell oil-modifiedphenol-formaldehyde resm.

4. An adhesive composition comprising a chemical adduct of maleicanhydride and a rubbery copolymer of from about 95 to about 99% ofisobutylene and from about 5% to about 1% of a conjugated diolefin, andin addition a cashew nut shell oil-modified phenol-aldehyde resin.

5. A composite article embodying an elastomer bonded 10 to anothermaterial by means of an adhesive composition as set forth in claim 1.

6. A composite article embodying an elastomer bonded to another materialby means of an adhesive composition as set forth in claim 2.

7. A composite article embodying an elastomer bonded to another materialby means of an adhesive composition as set forth in claim 3.

8. A composite article embodying an elastomer bonded to another materialby means of an adhesive composition as set forth in claim 4.

9. A composite article embodying an elastomer bonded to a textilematerial by means of an adhesive composition as set forth in claim 1.

10. A method of bonding an elastomer to other materials by applying andinterposing between said elastomer and the other material a cement of anadhesive composition as set forth in claim 1, and heating the assemblyuntil the elastomer and the other material are firmly bonded together.

11. An adhesive composition comprising a soluble, processable, chemicaladduct of maleic anhydride and an elastomer selected from the classconsisting of Hevea rubber; synthetic, rubbery homopolymers of aconjugated diolefin; rubbery heteropolymers of at most of a monoolefiniccompound and at least 15% of a conjugated diolefin; and rubberycopolymers of from about to about 99% of isobutylene and from about 5%to about 1% of a conjugated diolefin; and in addition a cashew nut shelloil-modified phenol-aldehyde resin capable of being converted to theinsoluble, infusible form by the action of a methylene-yieldinghardening agent and heat.

12. A composite article embodying an elastomer bonded to a textilematerial composed of nylon by means of an adhesive composition as setforth in claim 1.

13. A composite article embodying an elastomer bonded to a textilematerial composed of viscose rayon by means of an adhesive compositionas set forth in claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,532,374 Shepard et al. Dec. 5, 1950 2,652,353 Wilson Sept. 15, 1953FOREIGN PATENTS 507,995 Great Britain June 23, 1939 572,862 GreatBritain Oct. 26, 1945

1. AN ADHESIVE COMPOSITION COMPRISING A SOLUBLE, PROCESSABLE, CHEMICALADDUCT OF MALEIC ANHYDRIDE AND AN ELASTOMER SELECTED FROM THE CLASSCONSISTING OF HEVEA RUBBER; SYNTHETIC, RUBBERY HOMOPOLYMERS OF ANCONJUGATED DIOLEFIN; RUBBERY HETEROPOLYMERS OF AT MOST 85% OF AMONOOLEFINIC COMPOUND AND AT LEAST 15% OF A CONJUGATED DIOLEFIN; ANDRUBBERY COPOLYMERS OF FROM ABOUT 95% TO ABOUT 99% OF ISOBUTYLENE ANDFROM ABOUT 5% TO ABOUT 1% OF A CONJUGATED DIOLEFIN; AND IN ADDITION ACASHEW NUT SHELL OIL-MODIFIED PHENOL-ALDEHYDE RESIN.
 10. A METHOD OFBONDIONG AN ELASTOMER TO OTHER MATERIALS BY APPLYING AND INTERPOSINGBETWEEN SAID ELASTOMER AND THE OTHER MATERIAL A CEMENT OF AN ADHESIVECOMPOSITION AS SET FORTH IN CLAIM 1, AND HEATING THE ASSEMBLY UNTIL THEELASTOMER AND THE OTHER MATERIAL ARE FIRMLY BONDEND TOGETHER.